This prerequisite establishes a baseline for providing a minimum amount of outdoor air to buildings in order to maintain good indoor air quality and keep occupants comfortable and healthy. The prerequisite references ASHRAE 62.1-2007 (with errata but without addenda) and is often more stringent than local building codes, although it is not likely to entail any added costs.

The compliance paths for mechanically ventilated and naturally ventilated spaces, Case 1 and Case 2, are somewhat different and you may need to follow both paths for the same building on a space-by-space basis. Spaces served only by natural ventilation must follow the distinct requirements set out in Case 2, even if other spaces in the same building are mechanically ventilated and are following Case 1. Mixed-mode spaces which alternate between natural or mechanical ventilation must follow the compliance path for mechanical ventilation, Case 1.

Defining a Boundary

If all ventilation systems are included in the Core & Shell scope of work, then compliance with ASHRAE 62.1-2007 should be shown by the project team. If some or all ventilation systems are in the tenant’s scope of work, then compliance with ASHRAE 62.1 must be written into the lease agreement.  

If the project is speculative and no tenants have been identified yet, it’s up to the engineer to assume typical conditions. For example, a future office layout will probably have one or two conference rooms, a few private offices, and an open office area. Accounting for a reasonable distribution of space types will make it easier for future tenants to meet the ASHRAE standard.